You can see this issue if you look at a badlands biome in the Beta Vanilla preset. I'm not sure if this is to do with the preset itself or the fact the generator doesn't use vanilla's surface builders at all.

I'm aware. This is partly why I am not supporting vanilla biomes and only added a way to generate most of them in a world after many requests.

The vanilla surface builder was made even more tightly integrated with the vanilla noise methods with 1.19, so I could not properly get it to work with the modded terrain gen without significant issues.